The coupling element in the form of continuous coil is made of synthetic resin and comprises an interengaging head portion, a pair of upper and lower leg portions and a connecting reversed portion. Each of a pair of the coupling elements is attached along one edge of the fastener tape by sewing thread passing through the fastener tape at the points between each two loops of the coupling element.
A number of apparatuses for the purpose described above are known in which space sections devoid of coupling elements are formed in the slide fastener chain. Such prior art is exemplified by Japanese laid-open patent application No. 56-156104 (corresponding to BG Public Disclosure No. 2,074,923A, publicly disclosed on Nov. 11, 1981).
In this prior apparatus, as shown in FIG. 1-4, the slide fastener chain is supported on the die 21 so that the interengaged coupling elements occupy the lower position. The punch 12 having a cutting edge 10 is lowered from the upper position or from the fastener tape side to the interengaged coupling elements 14 through the space between the opposite fastener tapes 20 so that the cutting edge 10 cuts the lower leg portion of the interengaged coupling elements 14 on the interengaging head portion side of the sewing thread 18. Then, the ejector 16 is elevated from the coupling element side toward the upper leg portion of the coupling elements 14 so that the interengaged portion of the interengaged coupling elements 14 is held between the cutting edge 10 and the ejector 16. After that, the ejector 16 and punch 12 are elevated synchronously while holding the interengaged coupling elements 14 therebetween so that the coupling elements 14 are pulled away from or removed from the sewing thread 18, and thus from the fastener tapes 20. However, in this prior apparatus, the coupling elements 14 are not pulled away from the sewing thread 18 and remain on the fastener tape 20 if the grip of the coupling elements 14 by the punch 12 and the ejector 16 is insufficient or loose, or the sewing thread 18 is broken due to the excessive force for pulling the coupling elements 14 away from the sewing thread 18 if the grip of the coupling elements 14 is too tight, since (i) only the lower leg position of the coupling element 14 is cut off, and its cut position is on the interengaging head portion side of the sewing thread 18, (ii) the coupling elements 14 cut off at the lower leg portion are gripped on the interengaging head portion side of the sewing thread 18, pulled away from the sewing thread 18 and removed from the fastener tape 20, and (iii) the coupling elements 14 are attached firmly to the fastener tape 20.
The present invention overcomes the above mentioned difficulty such as failure of removing the coupling elements away from the sewing thread or breaking of the sewing thread. This invention has therefore for its primary object the provision of the apparatus for forming space sections devoid of the coupling elements having a predetermined length in the elongate slide fastener chain having the interengaged coupling elements easily and properly.